Q&A | What's safe for humans, and what's not?

The latest unsettling news about the widening melamine scandal — that fish meal used at state fish hatcheries and other fish-rearing operations also was tainted with the chemical — leaves consumers wondering what's safe to eat anymore and how to lower their risk when food-shopping or eating out.

Q: Have any contaminated fish made it into the food supply?

A: There have been no reports so far. But the fish meal tainted with melamine was sent to salmon farms as well as farms raising trout and other types of fish.

Six state fish hatcheries were among those receiving the food. The state Department of Fish and Wildlife said the tainted feed was pulled Tuesday.

Some of the juvenile fish that received the tainted food already have been released, but they are still small and won't be available for harvest for another three to four years.

Some of the tainted food also was tracked to hatcheries in Oregon. Federal officials haven't yet said where else the fish meal was used.

Q: Is it still safe to eat salmon and other fish? What about pork and chicken?

A: At this point, no food-safety experts or government agencies are calling for changes in the way people eat, order or shop for meat or fish as a result of the melamine scare.

The new U.S. "food czar," David Acheson of the Food and Drug Administration (FDA), said this on Tuesday:

"As with the situation with the poultry and the hogs, the levels that we're seeing in the fish meal are very comparable. ... We do not believe there is any significant human-health risk associated with consuming these fish."

The FDA also has not recalled any meat from animals fed contaminated products.

Scientists at five federal agencies conducted a risk assessment released Monday.

They found that even if a person ate only foods contaminated with melamine every day, at the same levels found in animals fed the tainted feed, the potential exposure was still about 2,500 times below the threshold considered unsafe.

Q: What is melamine?

A: Melamine is a small, nitrogen-containing molecule that has a number of industrial uses, including as an industrial binding agent, flame retardant and as part of a polymer in the manufacture of cooking utensils and plates. Melamine is also used as a fertilizer in some parts of the world, though it is not registered for use as a fertilizer in the United States.

Q: If this same chemical has sickened and killed pets, why is it considered a low risk for humans?

A: The tainted feed was not the sole food consumed by the animals and fish that received it.

It was diluted, mixed in with other kinds of feed, and that's important because it probably minimizes the risk of toxicity, said Michael Doyle, director of the Center for Food Safety at the University of Georgia.

At this point, it's not even clear that melamine enters the muscle tissue of fish and animals consumed by humans, noted Karen Killinger-Mann, consumer food-safety specialist with the Washington State University Extension Service.

Cats and dogs sickened by the melamine-tainted pet food suffered kidney damage, she noted, and the amount of melamine in their food may have been more concentrated.

The hogs and poultry eating tainted food haven't shown kidney problems and were exposed to lower overall levels of melamine.

In addition, melamine is not believed to accumulate in the bodies of animals; it is rapidly excreted in the urine, according to the FDA, and not metabolized.

Q: Should pregnant women, young children or the elderly take extra precautions?

A: Special populations are already warned to watch what fish they eat (some carry other toxins). The melamine scare has not prompted any new recommendations for those groups.

Q: OK, so they say the risk is low. But people now could be exposed to melamine from three different sources: fish, chicken and pork. Couldn't that raise the risk?

A: The FDA said it is doing another risk assessment on that issue. Right now, it's too soon to say.

Q: There's been a lot of talk about other contaminants that might cause a health risk to fish eaters. Are some fish safer to eat than others?

A: The state Department of Health encourages fish eaters to include a variety of fish in their diets, but also to limit consumption of fish that have higher levels of PCBs or mercury.

Q: What's the latest on the pet-food scare? What's safe to feed my cat or dog?

A: In the past two months, more than 100 pet-food products have been recalled because they were found to contain wheat flour and rice proteins spiked with melamine. As recently as last week, additional pet foods were placed on the list.

The FDA has confirmed more than a dozen pet deaths from melamine poisoning, although it reports getting some 10,000 complaints from pet owners, many of whom believe their pets were also poisoned by melamine.

Local pet-supply stores say some pet owners are switching to premium brands, raw foods or even making their own pet food as a result. Others are looking more closely at the ingredient list before they buy.

Q: What are officials doing to make sure this doesn't happen again?

A: The FDA and U.S. Department of Agriculture (USDA) say they are conducting full investigations and will continue to monitor imported wheat and corn gluten as well as rice-protein concentrate destined for human or animal consumption.

U.S. Customs and Border Protection is continuing laboratory testing of products as they enter the country. And the FDA is looking at a more comprehensive animal-feed safety system.

But critics say the widening scandal shows there are big holes in the government's food-safety system.

The U.S. imports about 15 percent of its food, a rate that's been doubling every five to 10 years, Doyle noted. At that rate, we could be importing more than half our food in the next 15 to 20 years.

Yet the FDA samples and tests less than 1 percent of imported food, Doyle said.

"What this has shown is how much contamination can occur throughout our food chain" when a toxin is introduced by an exporter and not caught by inspectors, he said.

"We're going to need pretty darn good procedures in place in coming years to ensure our food safety," he said. "I don't see a lot of federal action being taken to fix it."

Jolayne Houtz: jhoutz@seattletimes.com; 206-464-3122